Soldering iron



c. c. ABBOTT SOLDERING IRON Dec. 10,1940; 2,224,583

Filed July 30, 1936 2 Sheets-Sheet l by jv] H15 Attovrweg.'

Chafie C. Abbott,

C. C. ABBOTT SOLDERING IRON Dee. 10, 1940.

Filed July 30, 1936 2 Sheets-Sheet 2 Patented Dec. 10, 1940 UNITED STATES PATENT OFFICE SOLDEBING IRON New York Application July 30, 1938, Serial No. 93,411

13 Claims.

This invention relates to soldering irons, more particularly to electric soldering irons. and it has for its object the provision of an improved device of this character.

'I'his invention contemplates the provision of an improved organization of parts involving the soldering tip and heating element for the tip; and further contemplates improvements in the electrical connections for the heating element of the iron.

For a more complete understanding of this invention, reference should be had to the accompanying drawings in which Fig. 1 is a fragmentary elevation illustrating an organization of heating unit and soldering tip arranged in accordance with this invention, the organization being shown mainly in section, but having parts broken away so as to illustrate certain structural details; Fig. 2 is a fragmentary elevation mainly in section illustrating a handle structure used in the soldering iron of Fig. l, and showing improved electrical connections for the heating element arranged in accordance with this invention; Fig. 3 is a view similar to Fig. l, but illustrating a modified form of this invention; Fig. 4 is a view similar to Fig. 2, but illustrating the handle structure and electrical connections for the iron of Fig. 3; Fig. 5 is a sectional view taken through the line 5 5 of Fig. 4 and looking in the direction of the arrows; Fig. 6. is a fragmentary elevation of a handle structure oi' the type shown in Fig. 4, but of modied form, parts being shown in section so as to illustrate certain details of construction; Fig. 'l is an elevation of a soldering iron of modified form arranged in accordance with this invention; Fig. 8 is an enlarged sectional view of the heating unit and tip organization of the iron of Fig. 7, parts being broken away so as to illustrate certain details of construction; Fig. 9 is an enlarged sectional view of a portion of the handle structure of the iron of Fig. '7, parts being broken away so as to illustrate certain details of construction; and Fig. 10 is a sectional view of a heating element and soldering tip organization of modied form arranged in accordance with this invention.

Referring more particularly to Figs. l and 2, the invention has been shown in these figures as applied to a soldering iron having a working tip I0, a heating element .Il for applying heat to the tip I0, a metallic support I2 for the heating element and tip, and a handle I3 secured to the metallic support, whereby the iron may be manipulated.

(Cl. Mil- 26) As shown, the heating element II is of cylindrical form. This heating element may be of any suitable construction, but preferably will be of the sheathed type, such as described and claimed in my United States Patent No.1,698,289, dated January 8, 1929. As there described, the heating element comprises a resistance conductor 'Il wound upon an insulating core I5, and having a layer Il of heat conducting, electrically insulating material between the resistance conductor and core and an outer metallic casing I1. The insulating layer may be formed of any suitable material, such as magnesium oxide.

The cylindrical heating unit II is mounted in a cylindrical casing I8 arranged in spaced relation with the unit, as shown. The casing I8 at its handle end is rigidly secured to the metallic support I2. For this purpose, the support I2 is threaded from end to end, the casing having a corresponding threaded section at its handle end receiving the threads on the casing, as shown in Fig. 1. Preferably, the threads on the support I2 will be formed by rolling or spinning them from the stock of the walls of the tube itself, as clearly shown in Fig. 1. This provides a relatively large thread as shown, and increases the length of the heat path from the heating element to the handle. After the casing is threaded on the support I2, the walls of the threaded section of the casing and of the support I2 within it are deformed, as by means of a square split die (not shown), so as to securely lock the casing to the support.

The soldering tip I0 is secured in the end of the casing opposite the handle end. For this purpose, the tip I0 is provided with an enlarged portion I! having a centrally arranged bore 20 therein which receives the tip end of the heating element Il. A thread 2| is provided on the outer walls of the portion I9 which is received by a corresponding internal thread in the casing, as shown.

Secured to the outer surface of the heating unit II is a metallic sleeve 22, preferably formed of calorized copper. The sleeve 22 may be secured to the unit in any suitable manner, as by swaging the sleeve on the unit. 'I'he sleeve, as shown, is positioned intermediate the ends of the heating unit I I, the handle and of the sleeve bearing against a shoulder 23 provided for it on the casing I8, while the tip end serves as an abutment against which the portion I9 of the tip is forced when th( tip is screwed in. It will be observed in view of this arrangement that when the portion I9 is screwed inwardly so as to abut against the tip end of the sleeve it will draw the casing toward the left so that the abutment 23 is forced tightly against the handle end of the sleeve 22. Preferably, the tip end of the sleeve will be tapered downwardly toward the heating element, as indicated, and the portion I8 will be provided with a corresponding taper so that when the portion I8 is threaded inwardly it will function to center the casing with reference to the sleeve 22 and the heating element I I.

Relative rotary motion between the heating element Il and casing I8 is prevented by an interlock between these members formed by a slot or groove 24 formed in the outer wall of the sleeve 22 and a tongue 28 formed on the casing entering the slot. 'I'he tongue 28 preferably will be formed by pressing inwardly the stock of the casing, as shown. As shown, the slot 24 extends outwardly to the end of the sleeve so that the heating element can be moved outwardly through the tip end of the casing when it is desred to repair or replace the unit.

As pointed out previously, the metallic suport I2 is threaded from end to end. This member at its end opposite the tip receives the handle I3 in threaded engagement with it. The handle I3 is provided with a centrally arranged bore 28 having its tip end threaded, as'indicated by the numeral 21, tp receive the handle end of the metallic support I2.

Extending longitudinally through the metallic `member I2, substantially from end to end thereoi', is an insulating member 28 provided with a pair of spaced-apart passageways 28 through which a pair of leads 38 connected to the terminals of the heating element are directed. 'Ihe member 28 is formed of any suitable material, such as porcelain. The leads 38, as shown, project from the end of the insulator 28 into the tube I2.

Entering the bore 28 of the handle is a suitable electrical supply lead 3I comprising a pair of supply conductors 32 which are insulated and which are covered by a common insulating coating 33 formed of any suitable electrically insulating yielding material, such as rubber. The ends of the conductors 32 are bared, as shown, and are arranged in overlapping relation with the associated ends of the leads. The overlapped ends of the leads and conductors are secured together by means of conducting wires 34 Atightly wound about the ends, as shown in Fig. 2. and soldered after being wound.

An insulating sleeve 38 is inserted in the tubular member I2 about the portions of leads and conductors connected together. and these portions are separated by an insulating wall 38a. These members 38 and 35a preferably will be formed of a suitable insulating fiber.

The lead 3| is secured in the handle I3 against withdrawal by means of a pair of curved clamping members 38 positioned within the support I2 on opposite sides of the insulating coating 33, as shown. These members 38 are provided with oppositely inclined surfaces 31 and 38, preferably arranged at the tip end of the clamps. These inclined surfaces are arranged between a pair of clamping nuts 38 and 48 positioned on opposite sides of the surfaces and having threading engagement with the tubular support I2. The nuts as shown have wedglng or inclined faces engaging the inclined faces 31 and 38 of the clamps, and the nuts are turned inwardly toward each other sufficiently to force the clamping members 38 tightly against the insulated covering 38.

Preferably, the inner nut 38 will be fitted tightly against the insulating sleeve 38 to hold it in place, and will be rigidly secured to the support in any suitable manner, as by brazing. It may be secured by indenting the support into the nut.

It will be understood that the threaded connection between the handle I3 and the support i2 provides means whereby the position of the handle can be adjusted relative to the heating unit and tip organization.

In the form of the invention shown in Figs. 3 and 4, the tip 4I, heating element 42 therefor, casing 43 and sleeve 44 secured to the heating element are all arranged substantially as described in connection with Figs. 1 and 2, except that the thread in the casing 43 receiving the tip 4i is extended substantially through the length of the casing, as shown, as the thread in the'casing I8 of Fig. 1 may also be arranged. The long thread increases the average clearance space between the sleeve 44 and the casing. In the iron of Figs. 3 and 4, the supporting member 48 is of straight tubular form and is not threaded as is the corresponding support of the rst form. The tube 48, as shown, extends into the handle end of the casing 43 and is rigidly secured to the casing by a brazed or soldered joint 48. The inner end of the support 48 is turned inwardly, as indicated by the numeral 48a, substantially to the diameter of the heating element 42 in order to hold the handle end of the unit central with reference to the casing 43. In this case, the sleeve 44 is provided with a pair of lugs 41 diametrically opposite each other (only one shown) and projecting outwardly from the end of the sleeve, as shown. These lugs are received in similarly spaced recesses provided for them in the inclined part 48 of the sleeve. This arrangement prevents relative rotary motion between the heating element and casing 43 and support 48.

The support 48 is connected to the handle 48 by a connection means preventing direct conduction of heat from the support 48 to the handle. As shown, a handle ferrule 48 is provided between the tube 48 and the handle 48. This ferrule, as shown, has a portion 88 surrounding the tube 48 in spaced relation with lt and within this space there are provided a plurality of pins 8I spaced clrcumferentially of the tube 48, as shown in Fig. 5. 'I'hese pins have diameters such that they space the ferrule in substantially concentric relation with the tube 48, and so as to have line contact with the tube and ferrule. The pins 8| are rigidly secured to the tube and ferrule in any suitable manner, as by copper brazing.

The ferrule 48 is provided with a threaded section 82 which is positioned opposite a threaded section 83 provided on the handle. Lying within the threads on the handle and ferrule is a coiled member 84 formed of circular stock. This member, it will be observed. contacts the ferrule and handle with line contacts only.

It will be observed in view of the foregoing arrangement that the ferrule 48 is spaced a material distance from the metallic support 48 by the pins 8| and has very small direct thermal contact with the support. Also it will be observed that the ferrule is supported in spaced relation and has but line contact with the handle. The handle is, therefore, thermally insulated from the tube 48, and consequently, from the heating element and tip organization.

In this case, the insulating core 84 for the leads 55 oi' the heating element extends into a bore 58 provided for it in the handle. 'Ihe leads 55 are secured to the conductors 51 of the twin supply conductor or lead 58 by means of suitable eyelets 59. The end portions of the bare conductors and the leads will preferably be arranged side by side, as shown in Flg. 4, and then twisted together, and then the eyelets will be slipped over the twisted portions and compressed or swaged into tight engagement with the conductors. Then the eyelets will be folded over, as indicated in Fig. 4. Surrounding the connected portions of the leads and conductors is an insulating sleeve 60, and interposed between them is an insulating wall or barrier a. The outer end of the sleeve 60 rests against a shoulder 60h provided in the handle, as shown.

In this case, the twin supply conductor 58 is secured by `means of a plug or set screw 6| threaded in a bore 82 provided for it in the handle and arranged transversely of the bore 56. Opposite the bore 82 is an angular depression 63 into which the conductor is forced by the plug 6| when screwed inwardly sulciently. This locks the lead against withdrawal from the handle, and also prevents twisting of the cord relative to the handle.

In the modified form of the invention shown in Fig. 6, the ferrule 8l is secured in the same manner to the tubular support as is the ferrule 49 secured to the tube l5 of Fig. 4. In this case, however, the ferrule has a direct threaded connection 66 with the handle 81. In other words, the member 5I has been eliminated in this form. This form is particularly applicable to low voltage irons, such as those having a heating unit of '75 Watts.

In Figs. '1, 8 and 9 there is illustrated still another form of this invention. In this case, the heating element and tip organization 68 is secured to the handle 89 by means of a threaded metallic tubular member 10, as are the heating element and tip organization and handle of the rst form described in Figs. 1 and 2.-

Referring to Fig. 8, the heating element 1| is inserted in a tubular member 12 that is provided with a bore 13 extending through one end and substantially through the full length of the sleeve to receive the heating element. The sleeve 12 is provided with a saw cut or similar slit 14 to prevent the sleeve from sticking to the unit.

At its left-hand end, as viewed in Fig. 8, the sleeve 12 supports a soldering tip 14a. 'For this purpose, the sleeve is provided with a solid cylindrical extension 15 which receives the tip in threaded engagement, as shown, the tip having a bore 15a receiving the extension. Preferably, the threads on the portion 15 Will be formed in a coating 16 formed of a non-corrosive metal, such as silver, and the mating threads in the tip will be provided in a lining 11 in the tip bore 15a formed of a similar material. This connection eliminates corrosion in the threads and enhances the transfer of heat to the tip. The coating and lining are soldered to the extension 15 and tip respectively. If desired, instead of using the coating 16 and lining 11, the interior of the tip and the exterior of the extension 15 may be calorized.

Surrounding the sleeve 12 and in spaced relation with it is a casing 19. 'I'he casing 19 is provided at its tip end with a tapered section 80 which bears against a corresponding tapered section 8| provided on the sleeve 12. These tapered sections are brazed together. The casing, at its right-hand end is secured to the support 18 by means oi' a plug 82 which, as shown, is threaded on the support 10 and has an extension in the casing that has a threaded connection 83 with the casing, as shown. The plug 82 is further provided with an annular rim or head 8l overlying the adjacent edge of the casing. The casing, as shown, is provided with an angular seat 85 having two sides arranged substantially at to each other. This seat is positioned opposite an angilar shaped channel 86 arranged inthe extension 84 on the head. Between the seat 85 and channel 88 is a suitable washer 81 formed of any suitable material, such as aluminum. It will be understood that originally, the washer is fiat and that when the head is turned inwardly of the casing, it will force the washer into the shape shown against the two sides of the seat 85. Preferably, the channel 86 will have an angle less than the angle of the seat, such as 60", so that when the plug 82 is threaded inwardly, the washer will be forced tightly against the seat 85, as shown, and will be wedged tightly against the two faces of the channel 86. This effects an airtight joint between the plug and casing. An airtight brazed joint 88 is provided between the plug and the support 10.

The sleeve 12, as shown, has a reduced extension 12a that fits into the end of the support 10.

The support 10, as shown, is inserted in a bore 89 provided for it in the handle 89, the bore being threaded to receive the threaded support, whereby the position of the handle with reference to the tip may be adjusted. Here also, an insulated twin-supply conductor 90 is directed'into the bore 89 and its conductors 9| are connected to the leads 92 provided for the heating element 1|. The leads, as shown, are threaded through an insulating core 93 in the tubular support 10, and are electrically connected to the conductors 9| by means of coiled connector members 94 wrapped tightly around the abutting ends of the leads and conductors. Preferably, the coiled connectors will be soldered to the conductors and leads, the soldering material 95 lling the spaces between the ends of the conductors and leads, and those between the turns of the connectors, as clearly shown in Fig. 9. The leads and connectors where joined are separated by an insulating barrier 98 and the joints are surrounded by suitable tapes l 91, formed of insulating material. The whole is surrounded by an insulating tube 98 positioned in the tube 10 between the core 93 and a metallic nut 99 threaded on the support, as shown. The nut 99 is secured to the tube 10 by brazing or by indenting the tube into the nut.

Against the outer side of the nut 99 is an annular ilexible washer |00 formed of any suitable yielding material, such as rubber. On the outer side of the annular member is a plug |0| also having a threaded connection with the tube 10. The plug |0| is turned inwardly sufliciently to tightly compress the annular member |00 so that it is forced into the insulated covering for the twin-supply conductor, as indicated by the numeral |02. The adjacent ends of the plugs 99 and |01 will be tapered, as shown in Fig. 9, so that when the plug |0| is turned inwardly, the tapered edges will engage the yieldable member |00 to force the material of the member inwardly into the insulated covering 90. At the same time, the member |0| is forced tightly against the support 10. This arrangement rigidly secures the conductor 90 in the handle.

In the form of the invention shown in Fig.

10, the heating unit |03, the tip |04, the sleeve |05 surrounding the unit and supporting the tip, and the casing |06 are all substantially arranged as described in connection with Figs. '1, 8, and 9. The casing |06, however, is secured to the support |01 in somewhat different fashion. In this case, a suitable bushing |08 is threaded on the support |01 and is positioned within the handle end of the casing |06, as shown. The bushing |08 is rigidly secured to the casing by means of a brazed joint |09 which effects an air-tight connection between the bushing and casing. Preferably, the casing will be iiared outwardly somewhat and the bushing will be cut away to provide a channel in which the brazing material is placed. Between the inner end of the plug and the adjacent end of the sleeve |06 are suitable metallic spacing washers These washers center the heating unit, and reduce the flow of heat to the support |01.

Threaded on the sleeve |01 on the exterior of the casing is a nut ||2 turned in tightly against the casing. Preferably and as shown, the nut I2 will be of the cup type having an annular recess ||3 around the sleeve |01. Within this recess is placed a quantity of asbestos wicking ||4 compressed tightly inwardly against the outer surface of the bushing and the brazed connection |09, and inwardly against the walls of the tube |01, as shown. This effects an air-tight joint between the casing and tubular support.

Handle structures disclosed in Figs. 2, 4 and 9 are described and claimed in my copending application Serial No. 286,541, filed July 26, 1939, which application is a division of this application.

Thermal insulating means between the handle structure and heating element and tip, disclosed in Figs. 4, 5 and 6, are described and claimed in my copending application Serial No. 197,353, led March 22, 1938, which application is a division of this application.

While I have shown particular embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A soldering iron and the like comprising a cylindrical heating unit, a tubular casing around said unit, a handle structure attached to said casing at one end, a working tip in thermal relation with said heating unit secured to the other end of said casing and a tongue and groove connection between said casing and heating unit to prevent relative rotary movement between them.

2. A soldering iron and the like comprising a cylindrical heating unit, a sleeve rigidly secured to said unit having a longitudinal recess in one end, a casing surrounding said sleeve having a tongue pressed inwardly from the stock of said sleeve into said recess to prevent relative rotary movement between said sleeve and casing but providing for longitudinal movement between them to permit said heating unit and sleeve to be withdrawn from the casing, a handle structure secured to the end of said casing adjacent said tongue and recess bearing against said sleeve, and a soldering tip threaded into said casing at the other end bearing against the sleeve at this end and having a recess receiving the corresponding end of said heating unit.

3. A soldering iron and the like comprising a tubular member, a casing arranged axially of said tubular member rigidly secured to one end thereof, this end of the tubular member extending into the casing, a heating unit in said casing having one end abutting the said end of said tubular member, a soldering tip fitted into the outer end of said casing bearing against said heating unit and screwed in tightly to force said heating unit against said tubular member, and an interlock between said tubular member and heating unit preventing relative rotary movement between them.

4. A soldering iron and the like comprising a heating unit, a casing therefor, a support, a plug secured to said support forced into said casing and having a head overlapping the end of said casing, a washer between said head and casing, and said head and casing having a complementary angular seat and channel between which the washer is tightly pressed, the seat having a greater angle than the channel.

5. A soldering iron and the like comprising a heating unit, a casing therefor, a working tip at one end of said unit, a metallic member, a screw plug on said metallic member having an air-tight joint with it and threaded into the other end of said casing opposite said tip, an annular extension on said plug overlying the adjacent end of said casing, said end having an angular seat extending toward said extension and said extension having an angular channel opposite said seat of less angularity than said seat and a metallic washer between said seat and channel pressed tightly against the sides of said seat and channel by said plug when threaded into said casing so as to provide an air-tight joint between said casing and plug.

6. A soldering iron and the like comprising a metallic member having an elongated aperture extending into it through one end thereof, a heating unit inserted in said aperture, a working tip on the other end of said member, a casing around said metallic member, a supporting member having one end threaded, a plug threaded on said end, an air-tight joint between said plug and supporting member, said plug being threaded into the end of said casing opposite said tip, and an air-tight joint between said plug and said casing.

7. A soldering iron and the like comprising a metallic heat conducting member having a bore therein extending through one end thereof and substantially to the opposite end, a working tip secured to said latter end, a heating element inserted in said bore, said member having a portion adjacent said tip tapering downwardly toward the tip, a casing around said heat conducting member having a tapered portion fitted to the tapered part of said member, a plug threaded in the end of said casing opposite said tip, and a support threaded in said plug.

8. A soldering iron and the like comprising a tip, a heating element for said tip, a casing for said heating element, a metallic support entering said casing, means securing said casing to said support, and a part of said support in said casing having an interlocking connection with said heating element to prevent rotary motion of said heating element in said casing.

9. A soldering iron and the like comprising a tip, a heating element for said tip, a casing for said heating element, a metallic tubular support having one end entering said casing and tapered inwardly to engage said heating element to center it with reference to said casing, notches in the inclined part of said support'l and projections on said heating element entering said notches so as to lock said heatingelement against rotary movement in said casing, and means securing said casing to said support.

10. A soldering iron comprising a heating unit, a casing for said heating unit spaced therefrom, a soldering tip having a. section inserted in the space between said ca-sing and heating unit and having a bore receiving the adjacent end of said heating unit, and a stop in the opposite end of said casing preventing movement of said heating unit from said bore.

11. A soldering iron comprising a heating unit, a. casing for said heating unit spaced therefrom, a soldering tip having a section inserted in the space between said casing and heating unit and having a bore receiving the adjacent end of said heating unit, a stop in the opposite end of said casing preventing movement of said heating unit from said bore, and locking means associated with said heating unit to prevent rotary movement thereof relative to said casing.

12. A soldering iron comprising a heating unit, a cylindrical heat conducting member having a bore receiving said heating unit, a soldering tip in direct thermal relation with said heat conducting member, a casing having one end mounted directly on said heat conducting member, and a metallic support mounting the other end of said casing and having a section extending into said casing and associated with said heating unit to prevent displacement thereof in said casing.

13. A soldering iron comprising a cylindrical heating element, a casing around said cylindrical heating element in spaced relation with it, a heat conducting sleeve tightly fitted on said heating element, a. soldering tip having a threaded section inserted in the space between one end of said heating unit and casing and threaded in said casing and up tightly against said heat conducting sleeve, said section having a bore receiving the adjacent end of said heating unit, and an abutment in the other end of said casing to limit the inward movement of said sleeve.

CHARLES C. ABBOTT. 

